1. Field of the Invention
The present invention relates to a photochromic golf ball which changes from an initial white color to a different color when exposed to U.V. radiation such as direct sunlight. The present invention is directed more particularly to a photochromic golf ball in which a photochromic pigment is evenly dispersed in a cover layer and/or a transparent coating layer of the golf ball. The golf ball may have a white color when it is shielded from U.V. radiation and undergoes a color change when it is directly exposed to sunlight or other ultraviolet radiation.
2. Description of the Prior Art
Golf is a sport in which a player strikes a small ball with various clubs from a series of starting tees into a series of holes on a course. A player who holes out his ball in the fewest strokes wins. Although golfs place of origin is uncertain, it is believed that Scotland has the longest history. The standard course consists of 9 or 18 consecutively numbered “holes” (the playing areas leading to the cups). The cup measures 4.25 inches in diameter and 4.0 inches or longer in depth and is set into a smooth surface of closely cropped grass, called a green. While playing on a golf course, on average the players walk about 6–7 km over about 4–5 hours.
As golf has been recently popularized as a leisure sport, there is a highly increased demand for golf products, such as golf balls. Most golf balls are traditionally white in color. Occasionally, colored golf balls are used in the winter. Various pigments, such as organic, inorganic, phosphorescent, and fluorescent pigments may be used to provide for a pigmented golf ball. However, other than red or orange based colors used in winter play, pigmented balls are not widely used.
One basic principle underlying the rules of golf is that players must play only their own ball and the ball should not be touched (except to hit it with a club) until the ball reaches the green. Usually, four players play together in a golf game. When all the accompanying players use white golf balls of the same brand, confusion may arise about which golf ball is whose. In this case, each of the players discriminates his own ball from other's with the numerals or logos marked on the golf balls. However, if the markings cannot be seen for various reasons, for example, they are screened by the ground, grass, or other hindrances, the players cannot discriminate the golf balls without moving the golf balls in violation of the rules.
Colored golf balls provide one solution to the problem. That is, if four playing companions use golf balls with four different colors, they can easily discriminate among the golf balls without violating rules of play. From this point of view, there is a need for colored golf balls. However, most golf players prefer white golf balls to other colored ones. Additionally, in order for four companions to play golf with golf balls of different colors, as many as 12 golf balls would be needed according to the golf ball package system in current use (three per color x four colors).